evaluation of image-enhanced endoscopic technology using

IntroductionGastric cancer is the third leading cause of death from cancerdeath worldwide [1]. Early detection and therapy for gastriccancer can improve the 5-year survival rate to 96%; however,there is a high mortality rate for advanced gastric cancer [2].

Therefore, early diagnosis of cancer is important in the man-agement of gastric cancer.

White-light imaging (WLI) has been used as the standardendoscopic examination for identification of suspicious lesions,but it is difficult to make an accurate diagnosis of early gastriccancer (EGC) using only WLI. Several studies have indicated

Evaluation of image-enhanced endoscopic technology usingadvanced diagnostic endoscopy for the detection of earlygastric cancer: a pilot study

Authors

Daisuke Yamaguchi1, Shinya Kodashima2, Mitsuhiro Fujishiro1, 2, Satoshi Ono2, Keiko Niimi2, 3, Satoshi Mochizuki2,

Yosuke Tsuji2, Itsuko Asada-Hirayama2, Yoshiki Sakaguchi2, Satoki Shichijo2, Chihiro Minatsuki2, Nobutake

Yamamichi2, Kazuhiko Koike2

Institutions

1 Department of Endoscopy and Endoscopic Surgery,

Graduate School of Medicine, The University of Tokyo,

Tokyo, Japan

2 Department of Gastroenterology, Graduate School of

Medicine, The University of Tokyo, Tokyo, Japan

3 Center for Epidemiology and Preventive Medicine,


Tokyo, Japan

submitted 25.7.2016

accepted after revision 24.5.2017

Bibliography

DOI https://doi.org/10.1055/s-0043-113632 |

Endoscopy International Open 2017; 05: E825–E833

© Georg Thieme Verlag KG Stuttgart · New York

ISSN 2364-3722

Corresponding author

Shinya Kodashima, Department of Gastroenterology,


7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan

Fax: +81-3-5800-9015

[email protected]

ABSTRACT

Background and study aims Image-enhanced endoscopy

(IEE) plays an important role in early detection and detailed

examination of early gastric cancer (EGC). The current study

aimed to clarify the efficacy of IEE using advanced diagnos-

tic endoscopy for EGC detection without magnification.

Patients and methods We performed endoscopic exami-

nations without magnification in patients referred to our

hospital with a diagnosis of upper gastrointestinal tumor

detected through routine screening endoscopy. In this

study, we used three IEE technologies: narrow-band ima-

ging; blue laser imaging; and i-scan optical enhancement.

The detection rates for EGC between IEE and white-light

imaging (WLI) were compared.

Results Between July 2013 and June 2014, 156 patients

were enrolled. Among upper gastrointestinal tumors, we an-

alyzed endoscopic examination results of 119 lesions that

were histologically diagnosed as EGC in 109 patients. The

EGC detection rate in the IEE plus WLI groups was 77.3%. Al-

though the EGC detection rate in the IEE group was higher

than that in the WLI group (80.0% vs. 70.3%), there was no

significant difference between these two modalities. An im-

portant detection factor using IEEwas tumor circumference,

where the rate of detection in the anterior wall and lesser

curvature was significantly higher than that in the posterior

wall and greater curvature (P=0.046). An important detec-

tion factor using WLI was color variation, where the rate of

occurrence of a reddened or pale tumor was significantly

higher than that of normal colored tumors (P=0.030).

Conclusions The detection rate of EGC without magnifica-

tion was similar between the IEE group and the WLI group.

Important detection factors differed between IEE and WLI;

therefore, the IEE and WLI modalities have different charac-

teristics regarding EGC detection. Consequently, we pro-

pose to use both IEE and WLI in the evaluation of EGC.

Original article

Yamaguchi Daisuke et al. Evaluation of image-enhanced… Endoscopy International Open 2017; 05: E825–E833 E825

that sensitivity of WLI in diagnosis of superficial EGC varies from33% to 75% [3–5].

Image-enhanced endoscopy (IEE) is a technology that hasbeen developed to improve diagnostic ability [6]. IEE is mainlysubdivided into digital, optical-digital, and chromoendoscopymodalities; efficacy of optical-digital methods for the detectionand identification of gastrointestinal tumors has been fre-quently reported in recent years [7].

Narrow band imaging (NBI), which is classified as an optical-digital method [8], is an advanced endoscopic imaging technol-ogy that has recently been developed, in which spectral band-width filters are used to improve the accuracy of diagnosis [9].Although endoscopy using NBI is remarkably useful for differ-ential diagnosis of superficial gastric lesions that are identifiedunder white light [3, 5, 10], there seems to be very little evi-dence to justify routine use of NBI during routine screeningendoscopy; that is because of the poor light intensity gener-ated, which causes the image to appear darker especially inthe stomach and colon. Newer-generation NBI processors (290and 190 series) with a higher light intensity are currently beinglaunched commercially and studies using these processors areeagerly awaited [11]. NBI processors with higher light intensi-ties have been developed and may potentially improve detec-tion rates. Next-generation NBI colonoscopy represents a sig-nificant improvement in detection of colonic polyps [12].

Blue laser imaging (BLI) and i-scan optical enhancement (OE)are also classified as optical-digital methods. BLI uses a lasersource with a short wavelength, and i-scan OE uses optical fil-ters that limit the spectral characteristics of the illuminationlight to improve endoscopic observation of microsurface struc-tures and microvascular patterns in superficial mucosa [13]. BLIand i-scan OE have an observational mode with high-illumina-tion intensity, namely BLI-bright mode and i-scan OE mode 2,respectively; these modes may be promising developmentsnot only for characterization but also for screening of gastroin-testinal tumors, because they can maintain high-illuminationintensity [14–16]. Thus, recently developed IEE systems ensurethe illumination intensity for wide-range observation of thefully extended gastrointestinal lumen using high light intensity.Therefore, they are expected to also be useful for detection andidentification of EGC without magnification.

However, the effectiveness of the 3 IEE systems (NBI, BLI,and i-scan OE) in improving the detection rate for EGC inscreening endoscopy without magnification has not yet beensystematically evaluated. In the current study, we conducted adiagnostic trial using prospectively collected data involving the3 IEE systems regarding the EGC detection rate. We also inves-tigated the characteristics of factors associated with the detec-tion of EGC using IEE and WLI.

▶ Fig. 1 Endoscopic images of EGCs in the three IEE systems (NBI, BLI, and i-scan OE) and WLI. a EGC with NBI. b EGC with WLI using the EVISLUCERA ELITE system. c EGC with BLI. d EGC with WLI using the LASEREO system. e EGC with i-scan OE. f EGC with WLI using the EPK-i 7000system.

E826 Yamaguchi Daisuke et al. Evaluation of image-enhanced… Endoscopy International Open 2017; 05: E825–E833

Original article

Patients and methodsStudy subjects

This was a single-center prospective pilot diagnostic study. Pa-tients who had been previously diagnosed with upper gastroin-testinal tumors using screening endoscopy at our hospital orother hospitals between July 2013 and June 2014 were enrol-led. Written informed consent was obtained from patientswho met the inclusion criteria prior to study enrollment. We ex-cluded patients who refused to provide consent prior to exam-ination. Patients who had been diagnosed with advanced gas-tric cancer were excluded. The target sample size was set at100 patients, a number achievable within 1 year.

The study was initiated after approval by the Medical EthicsCommittee of the University of Tokyo Hospital and registrationin the University Hospital Medical Network Clinical Trial Regis-try (UMIN000011139) on July 7, 2013.

Endoscopy system and endoscopic procedure

Endoscopic examinations using WLI and IEE were performedusing 1 of 3 video-endoscopy systems: the EVIS LUCERA ELITEsystem (Olympus Medical Systems, Tokyo, Japan); the LASEREOsystem (Fujifilm Medical Co. Ltd., Tokyo, Japan); and the EPK-i7000 system (HOYA Corporation, PENTAX Lifecare Division, To-kyo, Japan). The 3 video-endoscopy systems were equippedwith each IEE technology, which was classified as the optical-digital method as follows: NBI for the EVIS LUCERA ELITE sys-tem; BLI for the LASEREO system; and i-scan OE for the EPK-i7000 system.

The NBI system allows for narrow-band observation usingthe original optical filters, and light in the blue to green regionis well absorbed by hemoglobin, providing good visualization ofcapillaries and vessels in the superficial mucosa [17–19]. In thecurrent study, we used newer-generation NBI processors (i. e.,the EVIS LUCERA ELITE system).

The BLI system has a unique illumination setup involving 2lasers and a white light phosphor, and we achieved clear anddetailed visualization of microsurface structures and microvas-cular patterns of the superficial mucosa [14, 15, 20]. We usedthe BLI-bright mode in this study.

In the i-scan OE mode 2, the main wavelengths of the shortand mid-wavelengths correspond to the peaks of the hemoglo-bin absorption spectrum, and light between these peaks is alsocontinuously emitted at low intensity by raising baseline trans-mittance to achieve the maximum amount of illumination [21].We used the i-scan OE system in mode 2.

Representative endoscopic images are shown in ▶Fig. 1.

Study design

We performed diagnostic endoscopy for detection of EGC re-garding the primary modality, using WLI followed by IEE (WLIgroup) or IEE followed by WLI (IEE group). Patients were ran-domly assigned to 6 groups as follows: O-IEE group (NBI fol-lowed by WLI); O-WLI group (WLI followed by NBI); F-IEE group(BLI followed by WLI); F-WLI group (WLI followed by BLI); H-IEEgroup (i-scan OE followed by WLI); and H-WLI group (WLI fol-

lowed by i-scan OE). The subjects were assigned by the envel-ope method just before the endoscopic observation. All endo-scopic observations were performed by an endoscopist whohad no information concerning the EGC patients (size, location,and numbers) but had only information on presence of EGC,and by an assistant endoscopist who had access to all previousinformation. After the observation using the primary modalitywas completed, the assistant endoscopist immediately record-ed results on the case record form (CRF). After completion ofthe CRF for the primary modality, a second observation usingthe secondary modality was performed and the results were re-corded on the CRF. Examination time was defined as the firstobservation time of endoscopic screening procedure for EGCusing IEE or WLI. In this study, when endoscopists detected asuspected lesion, they were classified as EGC. Successful detec-tion of EGC was defined as the agreement between detection ofEGC/suspected EGC and the histological diagnosis of biopsyspecimen after endoscopic screening procedure.

We compared the EGC detection rate between IEE and WLIgroups. In addition, we evaluated the EGC detection rate in IEEplus WLI groups. The detection rate in IEE plus WLI groups wasdefined as the total detection rate of the first and second obser-vation using IEE and WLI.

We also investigated characteristics of detection factors (tu-mor size, location, and circumference; color variation usingWLI, macroscopic classification; histological classification; anddepth of invasion) in IEE and WLI groups. Color variations con-cerning EGC in the WLI system were defined as normal and dif-ferent (reddened/pale). And we investigated 5 cases that couldnot be diagnosed using either IEE or WLI for the details.

In this study, 10 endoscopists (S. K., M. F., S.O., K.N., S.M.,Y. T., I. H., Y. S., S. S., C.M.) performed the procedures for diag-nosis of EGC using each of the 3 IEE modalities. All endoscopistshad experience with >40 cases of endoscopic submucosal dis-section and >100 cases of diagnosis of EGC using IEE such as

Gastric lesions 169 lesions in 128 patients

Esophageal lesions43 lesions in 28 patients

Early gastric cancer119 lesions in 109 patients

Excluded 19 patients:Indeterminate pathological diagnosis

Assessment for enrollment162 patients

Excluded 6 patients:Refused consent

▶ Fig. 2 Flowchart showing recruitment of patients in this study.


NBI, BLI and i-scan OE prior to this study. This experience re-duced the effect of the learning curve on the analysis.

Statistical analysis

We compared the EGC detection rate between IEE and WLIgroups, and the characteristics of detection factors in these

groups using the χ2 test and Student’s t-test. Univariable logis-tic regression analysis was performed to examine characteris-tics of detection factors adjusted for each of the other tumorfactors. Multivariable logistic regression analyses were per-formed using all tumor factors (tumor size, tumor lesion, tumorlocation, color variation, macroscopic classification, histologi-

▶ Table 1 Patients characteristics.

n IEE group WLI group P value

Number of patients 109 50 59

Median age (years) 70.3 ±10.8 69.7 ± 10.3 70.8 ±11.2 0.582

Sex 0.780

▪ Male 95 43 52

▪ Female 14 7 7

Number of tumor lesions 119 55 64

Examination time (min) 5.9 ± 2.0 5.7 ±2.1 6.1 ±2.0 0.312

Tumor size (mm) 16.8 ±13.2 17.4 ± 11.3 16.3 ±14.8 0.654

Tumor lesion 0.805

▪ Upper third 18 8 10

▪ Middle third 55 24 31

▪ Lower third 46 23 23

Tumor location 0.913

▪ Anterior wall 18 10 8

▪ Posterior wall 27 27 13

▪ Lesser curvature 47 24 23

▪ Greater curvature 27 16 11

Color variation 0.202

▪ Reddening 70 35 35

▪ Pale 21 6 15

▪ Normal 28 14 14

Macroscopic classification 0.298

▪ Elevated type (0-IIa) 33 19 24

▪ Flat type (0-IIb) 2 1 1

▪ Depressed type (0-IIc) 84 35 49

Histological classification 0.236

▪ Intestinal type 106 51 55

▪ Diffuse type 3 0 3

▪ Mixed type 10 4 6

Depth of invasion 0.782

▪ m 97 46 51

▪ sm1 10 3 7

▪ sm2 12 6 6


Original article

cal classification and depth of invasion) as independent vari-ables simultaneously. Odds ratios and 95% confidential inter-vals (CI) were determined by these uni- and multivariable logis-tic regression models. We also examined some cases of EGCthat were only detected using either IEE or WLI. A 2-tailed P val-ue <0.05 was considered to be statistically significant in all ana-lyses. All statistical analyses were performed using JMP version9.0.2 (SAS Institute, Tokyo, Japan).

ResultsBetween July 2013 and June 2014, 162 patients diagnosed withearly-stage tumors after previous endoscopic examinationswere enrolled in this study. We excluded 6 patients who refusedto give consent prior to examination. Additionally, 43 lesions in28 patients with esophageal lesions were excluded. Lesionsthat were histologically diagnosed as adenomas (6) and ad-vanced gastric cancers (9) were excluded from the study. In ad-dition, small lesions that were pathologically diagnosed as non-cancerous after examination of biopsy specimens were exclud-ed from the study. In total, 119 lesions in 109 patients were in-cluded in this study (▶Fig. 2).

▶Table 1 shows characteristics of patients who had EGC de-tected in the IEE and WLI groups. Ninety-five patients (87.2%)were male; mean (± SD) patient age was 70.3 ±10.8 years.Examination time (± SD) was 6.1±2.0 minutes. There was nosignificant difference between the IEE and WLI groups. Mean(± SD) EGC size was 16.8 ±13.2mm. EGCs were mainly locatedin the middle third of 55 lesions (46.2%) and in the lesser curva-ture of 47 lesions (39.5%). Using the gastric cancer macro-scopic classification, 84 (70.5%) lesions were primarily classi-fied as type 0-IIc. A total of 106 (89.1%) lesions were histologi-cally classified as being of the intestinal type. According todepth of invasion, 97 lesions (81.5%) were intramucosal can-

cers, and 10 lesions (8.4%) were submucosal cancers invadingto a depth of < 500mm. Twelve lesions (10.1%) were submuco-sal cancers invading to a depth of > 500mm.

Regarding color variation in the WLI group, 70 lesions(58.9%) were defined as reddened. There were no differencesin sex, age, tumor size and location, macroscopic and histolo-gical classification, depth of invasion or color variations be-tween IEE and WLI groups.

Finally, we categorized the lesions according to the 6 groupsas follows: 20 lesions in O-IEE group; 20 lesions in O-WLI group;15 lesions in F-IEE group; 24 lesions in F-WLI group; 20 lesions inH-IEE group; and 20 lesions in H-WLI group (▶Fig. 3).

The EGC detection rate is detailed in ▶Table 2. It was 77.3%in the IEE plus WLI groups. Although the rate was higher in theIEE group than in the WLI group (80.0% vs. 70.3%), there wasno significant differences between these 2 modalities. Amongthe 6 groups, the detection rate was 80.0% in the O-IEE group,60.0% in the O-WLI group, 86.7% in the F-IEE group, 79.2% inthe F-WLI group, 75.0% in the H-IEE group, and 70.0% in theH-WLI group; there was also no significant difference betweenthese 2 modalities using each endoscopic system.

Characteristics of detection factors between IEE and WLIgroups are compared in ▶Table 3. We analyzed the OR and95% CI for detection of tumor estimating uni- and multivariablelogistic regression analysis in IEE and WLI, respectively. Whenusing IEE methods, tumor circumference was significantly asso-ciated with tumor detection; the rate of detection of a tumor inthe anterior wall and lesser curvature was significantly higherthan that in the posterior wall and greater curvature, as deter-mined using univariable logistic regression analysis (OR 7.250,95%CI 1.370–38.300, P=0.020). This association was re-mained even after adjustment for each of the other tumor fac-tors (OR 6.700, 95%CI 1.140–39.400, P=0.035). Similarly, inWLI group, concerning color variation, a reddened or pale tu-mor was detected significantly more frequently than a normalcolor tumor determined (odds ratio 4.000, 95%CI 1.140–14.000, P=0.031) using univariate analysis. Using multivariablelogistic regression analysis, color variation was demonstrated

▶ Table 2 Early gastric cancer detection rate.

Tumor findings

n First

modality

Detection rate of

first modality (%)

P value

O-IEE 20 16 80.0 0.301

O-WLI 20 12 60.0

F-IEE 15 13 86.7 0.686

F-WLI 24 19 79.2

H-IEE 20 15 75.0 1.000

H-WLI 20 14 70.0

IEE group 55 44 80.0 0.291

WLI group 64 45 70.3

Early gastric cancer 119/109

(lesions/patients)

NBI/WLI40/36

O–IEE group20/18

O–WLI group20/18

F–IEE group15/15

F–WLI group24/21

H–IEE group20/17

H–WLI group20/20

BLI/WLI39/36

i-scan OE/WLI40/37

▶ Fig. 3 Flowchart showing the categorization of patients into6 groups.


to be an important detection factor concerning WLI independ-ently (odds ratio 4.510; 95%CI, 1.050–19.300; P=0.042).

In ▶Table 4, 5 cases involving detection of EGC using eitherIEE or WLI are presented. Three EGC cases were only detectedusing IEE, and all of these ECGs were located in the lesser curva-

ture. Two EGC cases were found exclusively using WLI, and inboth cases color variation involved reddened lesions. Repre-sentative endoscopic pictures of Case 3 and Case 5 are shownin ▶Fig. 4 and ▶Fig. 5, respectively.

▶ Table 3 Comparison between IEE and WLI systems for the detection of early gastric cancer.

IEE group

Univariable Multivariable

Odds ratio 95%CI P value Odds ratio 95%CI P value

Tumor size (mm)

▪ 1–20 0.246 0.028–2.130 0.203 0.236 0.021–2.620 0.240

Tumor lesion

▪ Upper and middle third 0.536 0.123–2.340 0.407 0.509 0.097–2.670 0.425

Tumor location

▪ AW and LC 7.250 1.370–38.300 0.020 6.700 1.140–39.400 0.035

Color variation

▪ Reddening and pale 0.274 0.031–2.380 0.240 0.320 0.031–3.320 0.340

Macroscopic classification

▪ Elevated type (0-IIa) 2.430 0.461–12.800 0.296 1.980 0.293–13.400 0.482

Histological classification

▪ Intestinal type 1.560 0.145–16.700 0.715 4.280 0.095–192.000 0.454

Depth of invasion

▪ m 1.360 0.237–7.780 0.732 1.010 0.133–7.700 0.990

WLI group

Univariable Multivariable

Odds ratio 95%CI P value Odds ratio 95%CI P value

Tumor size (mm)

▪ 1–20 0.147 0.018–1.220 0.076 0.129 0.011–1,460 0.098

Tumor lesion

▪ Upper and middle third 0.453 0.128–1.600 0.220 0.444 0.112–1.770 0.249

Tumor location

▪ AW and LC 1.010 0.332–3.070 0.986 0.879 0.238–3.240 0.846

Color variation

▪ Reddening and pale 4.000 1.140–14.000 0.031 4.510 1.050–19.300 0.042

Macroscopic classification

▪ Elevated type (0-IIa) 2.570 0.512–12.900 0.252 1.570 0.241–10.300 0.636

Histological classification

▪ Intestinal type 0.305 0.035–2.640 0.281 0.748 0.061–9.140 0.820

Depth of invasion

▪ m 0.436 0.086–2.210 0.316 0.845 0.134–5.320 0.858

AW, anterior wall; LC, lesser curvature


Original article

DiscussionThe NBI, BLI and i-scan OE were developed as each new IEE tech-nology for the early detection and detailed examination of EGC.These 3 modalities were classified the optical-digital methods,and considered with the same effect as IEE technology in clini-cal fields. Therefore, we categorized among 6 groups without adifference of IEE in this study.

IEE has been designed to improve visualization of microvas-cular and mucosal patterns in the gastrointestinal tract. Theusefulness of magnifying endoscopy involving IEE methods fordetection and diagnosis of EGC has been reported [22, 23].These methods appear to constitute a promising modality forimproving accuracy of diagnosing EGC. The IEE system was ex-pected to be useful for detection of EGC. However, in our study,there was no significant difference in EGC detection rate be-tween WLI and IEE. All patients with upper gastrointestinal tu-mors enrolled in this study had received biopsies approximately

1 month before to the study. In most of them, it was difficult toappraise the post-biopsy scars, Therefore, we think that suchscars did not have an influence on detection of EGC. In thisstudy, IEE missed 20% of EGC lesions and WLI missed 30% ofEGC lesions. We could not detect some lesions because theywere very small although the entire gastric region was ob-served with screening endoscopy. When we could not find thegastric lesions, we never looked for the gastric region again.Therefore, we might not detect the gastric lesions at a higherrate.

In the current study, we investigated characteristics of de-tection factors related to use of IEE and WLI. An important de-tection factor using IEE was tumor circumference, where therate of detection in the anterior wall and lesser curvature wassignificantly higher than in the posterior wall and greater cur-vature, determined using logistic regression analysis. The IEEsystem used in this study could brightly illuminate the gastricmucosa by means of strong light; however, in screening exam-inations, with IEE, gastric mucosa appeared slightly darker than

▶ Table 4 Cases involving detection of early gastric cancer using either the IEE or WLI.

Finding

modality

Tumor

size

Tumor

location

Tumor

circumference

Color

variation

Macroscopic

classification

Histological

classification

Depth of

invasion

Case 1 O-IEE 5 U LC Normal 0-IIc Intestinal m

Case 2 H-IEE 5 L LC Pale 0-IIc Intestinal m

Case 3 O-IEE 7 M LC Reddening 0-IIc Intestinal m

Case 4 O-WLI 8 U LC Reddening 0-IIc Intestinal m

Case 5 H-WLI 28 U PW Reddening 0-IIc Intestinal m

U, upper third; M, middle third; L, lower third; LC, lesser curvature; PW, posterior wall

▶ Fig. 4 Endoscopic images from Case 3. EGC was located in thelesser curvature of the lower part of the gastric body with WLI a andIEE b. The lesion was detected as erosion with WLI a but was ob-served as EGC with IEE b because of higher contrast and irregularvascular pattern between the cancer and surrounding tissue.

▶ Fig. 5 Endoscopic images from Case 5. EGC was observed as red-dened lesions in the lesser curvature of the upper part of the gastricbody only with WLI b. Lesions were not detected with IEE a, butwere only observed with WLI b, because of no difference betweenEGC and the surrounding red lesions in the intestinal metaplasia.


when viewed with the WLI system. Because tumor circumfer-ence was not an important detection factor using WLI, the dif-ference in detection rate as a result of tumor circumferenceusing IEE was believed to have been caused by differences inbrightness. Actually, when observing the dark area, we some-times found it difficult to recognize gastric lesions located in atangential direction or distant view; therefore, tumor circum-ference should be an important factor for detection of gastriccancer using IEE.

Color variation was an important detection factor whenusing WLI. Reddened or pale tumors were detected significant-ly more often than normal tumors using logistic regression a-nalysis. The difference in color between normal gastric mucosaand EGC is an important detection factor in screening examina-tions. Using WLI, it was obvious that it was difficult to detectnormal-colored tumors relative to reddened or pale tumors. Incontrast, using IEE it was possible to detect normal-colored tu-mors, and the detection rate was 85.7%. In our previous study,we demonstrated that IEE was significantly more effective indistinguishing the color difference between the normal epithe-lium and squamous cell carcinoma using the quantitative colordifference method (ΔE94) [16]. Similarly, IEE is considered to en-hance color differences between normal mucosa and normal-colored tumors; therefore, that modality may improve endo-scopic detection and characterization of normal-colored EGCas compared with WLI.

In our study, only 3 cases of EGC in the lesser curvature weredetected using IEE. IEE technology may lead to early detectionof gastric cancer and determination of a demarcation line with ashort-range view, such as the anterior wall and lesser curvature.

In some reddened tumors, we could easily distinguish be-tween EGC and surrounding normal mucosa using WLI ratherthan using IEE. We found that 2 EGC cases were not detectedusing IEE, and could only be observed using WLI. The i-scan OEmode 2 has been designed to improve the contrast related towhite-light observation by making the color tone of the overallimage closer to that of the natural color [22]. Therefore, somecases involving red lesions in surrounding normal mucosa wereoveremphasized using IEE. In these cases, differences betweenEGC and surrounding mucosa could not be determined.

Limitations of this study were the small number of cases en-rolled, and the fact that it was a single-institution study. In ad-dition, inclusion of patients was limited to those having gastricor esophageal lesions. Consequently, there would have beenselection bias regarding the participants. Further evidence isrequired from a larger-scale clinical trial of detection of EGCusing IEE.

ConclusionThis pilot study demonstrated that the EGC detection rate with-out magnification was similar between the IEE and the WLIgroups. However, IEE and WLI have different characteristicsassociated with detection of EGC. Our results suggest that EGCdetection without magnification may be more effective if IEEand WLI systems were used in combination for screening exam-inations.

AcknowledgmentsThe authors thank Dr. Hisako Yoshida, Clinical research centerof Saga University Hospital, for statistical advice.

Competing interests

None

References

[1] Muto M, Yao K, Kaise M et al. Magnifying endoscopy simple diagnosticalgorithm for early gastric cancer (MESDA-G). Dig Endosc 2016; 28:379–393

[2] Soetikno R, Kaltenbach T, Yeh R et al. Endoscopic mucosal resectionfor early cancers of the upper gastrointestinal tract. J Clin Oncol 2005;23: 4490–4498

[3] Ezoe Y, Muto M, Uedo N et al. Magnifying narrowband imaging ismore accurate than conventional white-light imaging in diagnosis ofgastric mucosal cancer. Gastroenterology 2011; 141: 2017–2025

[4] Maki S, Yao K, Nagahama T et al. Magnifying endoscopy with narrow-band imaging is useful in the differential diagnosis between low-grade adenoma and early cancer of superficial elevated gastric le-sions. Gastric Cancer 2013; 16: 140–146

[5] Kato M, Kaise M, Yonezawa J et al. Magnifying endoscopy with nar-row-band imaging achieves superior accuracy in the differential di-agnosis of superficial gastric lesions identified with white-lightendoscopy: a prospective study. Gastrointest Endosc 2010; 72:523–529

[6] Tajiri H, Niwa H. Recent Advances in Electronic Endoscopes: Image-enhanced endoscopy. JMAJ 2008; 51: 199–203

[7] Muto M, Minashi K, Yano T et al. Early detection of superficial squa-mous cell carcinoma in the head and neck region and esophagus bynarrow band imaging: a multicenter randomized controlled trial.J Clin Oncol 2010; 28: 1566–1572

[8] Yao K, Doyama H, Gotoda T et al. Diagnostic performance and limita-tions of magnifying narrow-band imaging in screening endoscopy ofearly gastric cancer: a prospective multicenter feasibility study. Gas-tric Cancer 2014; 17: 669–679

[9] Yao K, Anagnostopoulos GK, Ragunath K. Magnifying endoscopy fordiagnosing and delineating early gastric cancer. Endoscopy 2009; 41:462–467

[10] Yao K, Iwashita A, Tanabe H et al. Novel zoom endoscopy techniquefor diagnosis of small flat gastric cancer: a prospective, blind study.Clin Gastroenterol Hepatol 2007; 5: 869–878

[11] Subramanian V, Ragunath K. Advanced endoscopic imaging: a reviewof commercially available technologies. Clin Gastroenterol Hepatol2014; 12: 368–376.e1

[12] Horimatsu T, Sano Y, Tanaka S et al. Next-generation narrow bandimaging system for colonic polyp detection: a prospective multicen-ter randomized trial. Int J Colorectal Dis 2015; 30: 947–954

[13] Osawa H, Yamamoto H. Present and future status of flexible spectralimaging color enhancement and blue laser imaging technology. DigEndosc 2014; 26: 105–115

[14] Kaneko K, Oono Y, Yano T et al. Effect of novel bright image enhancedendoscopy using blue laser imaging (BLI). Endosc Int Open 2014; 2:E212– E219

[15] Yoshida N, Yagi N, Inada Y et al. Ability of a novel blue laser imagingsystem for the diagnosis of colorectal polyps. Dig Endosc 2014; 26:250–258


Original article

[16] Kodashima S, Fujishiro M, Ono S et al. Evaluation of a new image-en-hanced endoscopic technology using band-limited light for detectionof esophageal squamous cell carcinoma. Dig Endosc 2014; 26: 164–171

[17] Sano Y, Ikematsu H, Fu KI et al. Meshed capillary vessels by use ofnarrow-band imaging for differential diagnosis of small colorectalpolyps. Gastrointest Endosc 2009; 69: 278–283

[18] Uedo N, Ishihara R, Iishi H et al. A new method of diagnosing gastricintestinal metaplasia: narrow-band imaging with magnifying endos-copy. Endoscopy 2006; 38: 819–824

[19] Kuznetsov K, Lambert R, Rey JF. Narrow-band imaging: potential andlimitations. Endoscopy 2006; 38: 76–81

[20] Miyaki R, Yoshida S, Tanaka S et al. A computer system to be used withlaser-based endoscopy for quantitative diagnosis of early gastric can-cer. J Clin Gastroenterol 2015; 49: 108–115

[21] Neumann H, Fujishiro M, Wilcox CM et al. Present and future per-spectives of virtual chromoendoscopy with i-scan and optical en-hancement technology. Dig Endosc 2014; 26: 43–51

[22] Tsuji Y, Ohata K, Sekiguchi M et al. Magnifying endoscopy with nar-row-band imaging helps determine the management of gastric ade-nomas. Gastric Cancer 2012; 15: 414–418

[23] Yao K, Anagnostopoulos GK, Ragunath K. Magnifying endoscopy fordiagnosing and delineating early gastric cancer. Endoscopy 2009; 41:462–467

CORRECTION

Daisuke Yamaguchi, Shinya Kodashima, MitsuhiroFujishiro et al. Evaluation of image-enhancedendoscopic technology using advanced diagnosticendoscopy for the detection of early gastric cancer:a pilot study.Endoscopy International Open 2017,DOI: 10.1055/s-0043-113632The order of ▶Fig. 1 was corrected. This was corrected inthe online version on September 21, 2017.


evaluation of image-enhanced endoscopic technology using

Documents